U2AF1 and acute myeloid leukemia: It is possible that AML patients that have chromatin‐spliceosome mutations may have had a prodromal MDS period even if they did not necessarily meet the formal criteria for AML with myelodysplasia‐related changes (AML‐MRC).35 In fact, a study of 194 patients with rigorously defined s‐AML found that mutations in SF3B1, SRSF2, U2AF1, ZRSR2, ASXL1, EZH2, BCOR, or STAG2 was >95% specific for the diagnosis of s‐AML.24 When mutations in these genes were found in de novo AML, they conferred the same poor prognosis as seen in s‐AML.